Forums, Engine, Gearbox, Stern Gear, etc, Cracks in rudder spine and possible disalignment

blueheron at 18/03/2016 01:36:00
Hi co32 members, I hope you can help us.

I have some severe issues with the rudder on CO32 Blue Heron (1971)

- I get less stbd turn than port.
- There are cracks running vertical from top and bottom in the neck of the rudder.

Attached some photos, as you can see the big crack although at centre is much more visible when rudder is steering to port – explains on thing!

Whilst removing the skeg cap and the 3 machine screws, I found the aftmost screw to be almost corroded away just behind the screw-head. None of the screws were very tight, I could almost open them with my fingernail. The centre screw was actually a (thicker) bolt and this was a bit tighter. Were they fitted like that? (1971) Or perhaps this indicates this is not the first rudder removal for this boat? (we adopted her in 2009)

Any repair advice appreciated – alas a budget is not existent so a new rudder is not an option this year.

Alan
Blue Heron


UPPER CRACK – VIEW FROM STBD


LOWER CRACK – view from STBD


UPPER CRACK – VIEW FROM PORTSIDE

blueheron at 18/03/2016 10:42:19
Also Having difficulty releasing the rudder stock from the shaft. I have tried as suggested by the Technical paper CO32 rudder removal (by levering the block up and bashing it) but to no avail.
Also tried some pressure down on the stock (centre) with a gear puller braced on the external stainless steel block – but not sure there is something else preventing release so scared to really apply it hard.

There is a rectangular hole as you see from the top – no grub screw in there as far as I can find… Any ideas?


top view


no grubs I can see



side view no grubs I can find

George Isted at 18/03/2016 13:58:16
Not seen a Co32 tiller block on the top of the rudder stock like that before, normally it’s a solid bronze block but as your boat is an early boat it’s possible that was fitted from new (although looks like it has had a repair or two).

That rudder has seen better days. If you can’t replace it I’m sure that with care it can be repaired. Once off you will need to grind out that crack so that there is plenty of surface area each side to bond too then rebuild with resin and glass matt. It’s very likely that the rudder will have some water in it so I suggest you drill a couple of holes to let that drain before re-sealing.

You may not wish to hear it but I would be very tempted to get a new rudder.

Have you tried a hub puller to remove the tiller block from the stock? Or you can (with the heel fitting removed and the rudder loosely supported) put a suitable sized socket on the top of the stock and hit it with a lump hammer. I normally do the latter and a couple of healthy taps will separate the two.

George Isted at 18/03/2016 14:00:29
Looks to me as though there are a couple of hairline cracks in the rudder block (STBD side), I suggest you inspect and repair/replace if necessary.

Richard Ritchie at 18/03/2016 21:20:59
Note that there is a key in the “square hole” that you describe.
This is a safety device: the torque is taken on the cone fitting of the rudder head. Make sure this is well seating when you replace.
The key will normally need to go back the same way round. It tends to have taken up the shape….
At the heel plate: originally the machine screws went into fibreglass, and tend to work loose. Many people have put in a tapped steel plate when refurbishing.
Note that the rudder hangs from the top: the heel plate is there for sideways forces only.
(Mine is in pieces at present, but in order to replace prop shaft, not rudder.)
Good luck
Richard

doug at 20/03/2016 11:06:56
Hello Blueheron,

I am sure you could resurrect the rudder for not much money but a fair deal of effort. It gets easier once you have the rudder off and on the bench. I agree with the others generally and feel that you should open the rudder right up and inspect the internal welded tangs while you are at it – there is a paper by JR on the subject, I think – check on the home page. This would help you in making a more complete repair.

The heel plate could be opened up for larger set screws and the holes in the skeg re-drilled and tapped – any damage would need to be made good first.

I also agree that the top block looks suspect, is it stainless steel? There is good reason for the bronze block normally fitted in that steel on steel can gall together and be almost impossible to remove, even with an hydraulic puller. If this is the case I would cut if off and replace with the standard item, it would be expensive but I really would do it. If the taper has been tampered with, a local engineering firm could make a block to suit. Best of luck with the job.

blueheron at 21/03/2016 13:58:29
@doug top block is stainless yes – but there appears to be no “key” in the rectangular hole – it appears to be quite empty. will try to get some light in there and see if it has dropped or perhaps corroded away.

thanks all for your helpful responses!

waratah912 at 25/03/2016 22:20:21
Try giving it a daily dose of plus gas for a couple of weeks, then refit the bolt so that it is just clear of the stainless fitting, heat it as hot as you can get it without damaging the surrounding cockpit sides / floor, use heat proof tiles or similar for protection. Fit the puller and do it up a tight as you can, then hit the end hard with a heavy hammer. the shaft should then drop by however much clearance you originally left between the bolt and the stainless fitting. Be brave, because the alternatives are worse.
If that doesn’t work, you’re in to cutting it off, which is going to be a bitch. I’d start by taking an angle grinder to the fitting down the keyway – less chance of damaging the shaft, less steel to cut and accessible. You’re not going to be able to go all the way down, but you might get enough that a cold chisel driven into the top of the gap would open the fitting on the taper enough to break the stiction.

Keny at 28/03/2016 11:51:27
Just to add to above . Try cutting through the vertical welding with a thin s/s disc. If you can separate the outer casing everything else will be a lot easier. Also tapers are often successfully removed by hitting them sideways with a backing weight of some sort.
keny

blueheron at 08/05/2016 11:16:09
Okay, so just to update…

After three efforts at heating & ‘persuading’, she eventually dropped… Yeh!

Thanks for all your comments…

Now it’s time to cut the rudder in half…

As per:

http://contessa.simdif.com/exterior.html
&
http://therebepirates.com/2010/12/02/maintenance-is-expensive-crevice-corrosion-in-the-rudder-stock/

Wish me luck!

If anyone’s done this before, any detailed log of the experience…?

rob at 28/10/2016 14:50:15

Hi There, this spring I decided to take the rudderstock out of the rudder for inspection. Depending the state of the rudder and the stock after removal I was to decide to build a whole new rudder or do a repair. In a previous attempt I tried to open it up and bond as good as it gest everything together but after a year at appeared to be leaking again where the stock enters and leaves the rudder. Apparantly that didn’t work. After opening the rudder the whole inside was very wet and polyurethene foam came out soaked with water. The shaft came out with a heavy form of crevis corrosion and needed to be replaced. The rudder itself came out pretty well and I decided to re-use it. I cleaned and dried it extensively and filled the rudder again with a new stock and a decent Quality Marine grade PVC foam. I did spend some labour myself and outsourced around 250 euro’s on stainless steel work ( welding and machining) but the rudder looks and works fine again. For those interested I have some pictures taken during the process which I can send. I tried to place them in this forum but I did not succeed. To my opinion you should have a little bit more more then average skill in working with composites to perform the job yourself.

davidleech at 05/04/2019 09:28:16

Hi Rob
Just splitting rudder myself and scenario sounds similar – wet inside, smelling fine though and glasswork looks good, but indication of some corrosion on stock. Really would appreciate photos and any info on best line to open up so extraction of stock easy but easy assembly for retaining strength.
many thanks